我正在写一个基本插件。这是我的代码：

$new_user = get_userdata($user_id);

$first_name1 = $new_user->user_firstname;
$last_name1 = $new_user->user_lastname;
    echo "<" . $first_name1 . $last_name1 . ">";
    //returns: <>

$first_name2 = $new_user-first_name;
$last_name2 = $new_user->last_name;
    echo "<" . $first_name2 . $last_name2 . ">";
    //returns: <>

根据the codex, 这应该行得通，但当我回音时$first_name 或$last_name 它们是空的。奇怪的是，这确实有效：

    $id = $new_user->ID;

我做错什么了吗？

更新时间：

我var_dump教育部$new_user 那些财产不在那里！这是因为我从/mu plugins目录中的插件中调用它吗？这些属性是否稍后添加？

object(WP_User)#334 (7) { ["data"]=> object(stdClass)#330 (10) { ["ID"]=> string(3) "758" ["user_login"]=> string(7) "emerson" ["user_pass"]=> string(34) "$P$BB2PuvRbyGUSVZR1M8FLSujPvMO2MW0" ["user_nicename"]=> string(7) "emerson" ["user_email"]=> string(16) "123esl@gmail.com" ["user_url"]=> string(0) "" ["user_registered"]=> string(19) "2012-08-17 01:03:27" ["user_activation_key"]=> string(0) "" ["user_status"]=> string(1) "0" ["display_name"]=> string(7) "emerson" } ["ID"]=> int(758) ["caps"]=> array(1) { ["subscriber"]=> string(1) "1" } ["cap_key"]=> string(15) "wp_capabilities" ["roles"]=> array(1) { [0]=> string(10) "subscriber" } ["allcaps"]=> array(15) { ["read"]=> bool(true) ["level_0"]=> bool(true) ["read_questions"]=> bool(true) ["read_answers"]=> bool(true) ["publish_questions"]=> bool(true) ["immediately_publish_questions"]=> bool(true) ["publish_answers"]=> bool(true) ["read_private_forums"]=> bool(true) ["publish_topics"]=> bool(true) ["edit_topics"]=> bool(true) ["publish_replies"]=> bool(true) ["edit_replies"]=> bool(true) ["assign_topic_tags"]=> bool(true) ["access_s2member_level0"]=> bool(true) ["subscriber"]=> string(1) "1" } ["filter"]=> NULL } 

$new_user = get_userdata($user_id);

// get all the meta data of the user
$new_user_data = get_user_meta( $user_id );

// get the first name of the user as a string
$new_user_firstname = get_user_meta( $user_id, \'first_name\', true );

$first_name = $new_user->first_name;
$last_name = $new_user->last_name;